How would you suggest that I transcribe an arrangement like the one below where a vocal line is to be included with an instrumental portion for harmonic analysis?
You could do either open score or piano (all intervals read upward) with solo line.
If you have other pieces (such as the Bach you asked me about) that are in the same volume, I’d use a similar format for each if possible. The important thing is to be consistent. If you have multiple formats, just include a TN before the example saying which format you’re using.